Field of the Invention
The present invention relates to a water droplet detection device and a three-dimensional object detection device that uses the water droplet detection device.
Background Information
On-board monitoring devices for vehicles that use CCD cameras are known to include a lens for capturing a first focal point distance for near distances used for imaging rain droplets that have attached to the vehicle and a second focal point distance for far distances used for imaging the vehicle periphery, and a camera unit that switches the lens focal point distance between the first focal point distance and the second focal point distance. When the presence of rain droplets is to be detected, a switch is made to the first focal point distance, whereas when the periphery of the vehicle is to be monitored, a switch is made to the second focal point distance (Japanese Laid-Open Patent Application No. 2005-225250).